Novel Wearable Device for Mindful Sensorimotor Training: Integrating Motor Decoding and Somatosensory Stimulation for Neurorehabilitation.

Sensorimotor impairment is a prevalent condition requiring effective rehabilitation strategies. This study introduces a novel wearable device for Mindful Sensorimotor Training (MiSMT) designed for sensory and motor rehabilitation. Our MiSMT device combines motor training using myoelectric pattern recognition along sensory training using two tactile displays. This device offers a comprehensive solution, integrating electromyography and haptic feedback, lacking in existing devices. The device features eight electromyography channels, a rechargeable battery, and wireless Bluetooth or Wi-Fi connectivity for seamless communication with a computer or mobile device. Its flexible material allows for adaptability to various body parts, ensuring ease of use in diverse patients. The two tactile displays, with 16 electromagnetic actuators each, provide touch and vibration sensations up to 250 Hz. In this proof-of-concept study, we show improved two-point discrimination after 5 training sessions in participants with intact limbs (p=0.047). We also demonstrated successful acquisition, processing, and decoding of myoelectric signals in offline and online evaluations. In conclusion, the MiSMT device presents a promising tool for sensorimotor rehabilitation by combining motor execution and sensory training benefits. Further studies are required to assess its effectiveness in individuals with sensorimotor impairments. Integrating mindful sensory and motor training with innovative technology can enhance rehabilitation outcomes and improve the quality of life for those with sensorimotor impairments.

Hypnotic suggestions cognitively penetrate tactile perception through top-down modulation of semantic contents.

Perception is subject to ongoing alterations by learning and top-down influences. Although abundant studies have shown modulation of perception by attention, motivation, content and context, there is an unresolved controversy whether these examples provide true evidence that perception is penetrable by cognition. Here we show that tactile perception assessed as spatial discrimination can be instantaneously and systematically altered merely by the semantic content during hypnotic suggestions. To study neurophysiological correlates, we recorded EEG and SEPs. We found that the suggestion "your index finger becomes bigger" led to improved tactile discrimination, while the suggestion "your index finger becomes smaller" led to impaired discrimination. A hypnosis without semantic suggestions had no effect but caused a reduction of phase-locking synchronization of the beta frequency band between medial frontal cortex and the finger representation in somatosensory cortex. Late SEP components (P80-N140 complex) implicated in attentional processes were altered by the semantic contents, but processing of afferent inputs in SI remained unaltered. These data provide evidence that the psychophysically observed modifiability of tactile perception by semantic contents is not simply due to altered perception-based judgments, but instead is a consequence of modified perceptual processes which change the perceptual experience.

Synchronous motor imagery and visual feedback of finger movement elicit the moving rubber hand illusion, at least in illusion-susceptible individuals.

Recent evidence suggests that imagined auditory and visual sensory stimuli can be integrated with real sensory information from a different sensory modality to change the perception of external events via cross-modal multisensory integration mechanisms. Here, we explored whether imagined voluntary movements can integrate visual and proprioceptive cues to change how we perceive our own limbs in space. Participants viewed a robotic hand wearing a glove repetitively moving its right index finger up and down at a frequency of 1 Hz, while they imagined executing the corresponding movements synchronously or asynchronously (kinesthetic-motor imagery); electromyography (EMG) from the participants' right index flexor muscle confirmed that the participants kept their hand relaxed while imagining the movements. The questionnaire results revealed that the synchronously imagined movements elicited illusory ownership and a sense of agency over the moving robotic hand-the moving rubber hand illusion-compared with asynchronously imagined movements; individuals who affirmed experiencing the illusion with real synchronous movement also did so with synchronous imagined movements. The results from a proprioceptive drift task further demonstrated a shift in the perceived location of the participants' real hand toward the robotic hand in the synchronous versus the asynchronous motor imagery condition. These results suggest that kinesthetic motor imagery can be used to replace veridical congruent somatosensory feedback from a moving finger in the moving rubber hand illusion to trigger illusory body ownership and agency, but only if the temporal congruence rule of the illusion is obeyed. This observation extends previous studies on the integration of mental imagery and sensory perception to the case of multisensory bodily awareness, which has potentially important implications for research into embodiment of brain-computer interface controlled robotic prostheses and computer-generated limbs in virtual reality.

Sensory Target Detection at Local and Global Timescales Reveals a Hierarchy of Supramodal Dynamics in the Human Cortex.

To ensure survival in a dynamic environment, the human neocortex monitors input streams from different sensory organs for important sensory events. Which principles govern whether different senses share common or modality-specific brain networks for sensory target detection? We examined whether complex targets evoke sustained supramodal activity while simple targets rely on modality-specific networks with short-lived supramodal contributions. In a series of hierarchical multisensory target detection studies (n = 77, of either sex) using EEG, we applied a temporal cross-decoding approach to dissociate supramodal and modality-specific cortical dynamics elicited by rule-based global and feature-based local sensory deviations within and between the visual, somatosensory, and auditory modality. Our data show that each sense implements a cortical hierarchy orchestrating supramodal target detection responses, which operate at local and global timescales in successive processing stages. Across different sensory modalities, simple feature-based sensory deviations presented in temporal vicinity to a monotonous input stream triggered a mismatch negativity-like local signal which decayed quickly and early, whereas complex rule-based targets tracked across time evoked a P3b-like global neural response which generalized across a late time window. Converging results from temporal cross-modality decoding analyses across different datasets, we reveal that global neural responses are sustained in a supramodal higher-order network, whereas local neural responses canonically thought to rely on modality-specific regions evolve into short-lived supramodal activity. Together, our findings demonstrate that cortical organization largely follows a gradient in which short-lived modality-specific as well as supramodal processes dominate local responses, whereas higher-order processes encode temporally extended abstract supramodal information fed forward from modality-specific cortices.SIGNIFICANCE STATEMENT Each sense supports a cortical hierarchy of processes tracking deviant sensory events at multiple timescales. Conflicting evidence produced a lively debate around which of these processes are supramodal. Here, we manipulated the temporal complexity of auditory, tactile, and visual targets to determine whether cortical local and global ERP responses to sensory targets share cortical dynamics between the senses. Using temporal cross-decoding, we found that temporally complex targets elicit a supramodal sustained response. Conversely, local responses to temporally confined targets typically considered modality-specific rely on early short-lived supramodal activation. Our finding provides evidence for a supramodal gradient supporting sensory target detection in the cortex, with implications for multiple fields in which these responses are studied (e.g., predictive coding, consciousness, and attention).

The role of visual expectations in acupuncture analgesia: A quantitative electroencephalography study.

Acupuncture is a complex treatment comprising multisensory stimulation, including visual and tactile sensations and experiences of body ownership. The purpose of this study was to investigate the role of these three components of acupuncture stimulation in acupuncture analgesia. 40 healthy volunteers participated in the study and received acupuncture treatment under three different conditions (real-hand, rubber-hand synchronous, and rubber-hand asynchronous). The tolerance for heat pain stimuli was measured before and after treatment. Brain oscillation changes were also measured using electroencephalography (EEG). The pain tolerance was significantly increased after acupuncture treatment under all three conditions. Noticeable deqi (needle) sensations in response to acupuncture stimulation of the rubber hand were found under both rubber-hand synchronous and rubber-hand asynchronous conditions. Deqi sensations were significantly correlated with acupuncture analgesia only under the rubber-hand synchronous condition. Increased delta and decreased theta, alpha, beta, and gamma waves were observed after acupuncture treatment under all three conditions. Our findings clarified the role of cognitive components of acupuncture treatment in acupuncture analgesia through the rubber-hand illusion. This study is a first step toward separating various components of acupuncture analgesia, i.e. visual, tactile, and body ownership, and utilizing those components to maximize analgesic effects.

Touching you, touching me: Higher incidence of mirror-touch synaesthesia and positive (but not negative) reactions to social touch in Autonomous Sensory Meridian Response.

The characterisation of autonomous sensory meridian response (ASMR) as an audio-visual phenomenon overlooks how tactile experiences are not just perceptual concurrents of ASMR (i.e., tingling) but also commonly strong ASMR inducers. Here we systematically investigated whether ASMR-responders show altered tactile processing compared to controls. Using a screening measure of vicarious touch with a predefined cut-off for mirror-touch synaesthesia (MTS; a condition where tactile sensations are experienced when viewing, but not receiving, touch), we found that ASMR-responders had more frequent and intense vicarious touch experiences, as well as a strikingly higher incidence of MTS, than non-responders. ASMR-responders also reported greater reactivity to positive, but not negative, interpersonal touch. Correlations further showed these patterns to be more prevalent in those responders with stronger ASMR. We discuss the implications of our findings in terms of heightened sensory sensitivity, bodily awareness, and the underlying neuro-cognitive mechanisms driving vicarious tactile perception in ASMR and MTS.

Social Touch Somatotopically Affects Mental Body Representations.

In pre-Covid days, many daily actions such as hand shaking or cheek kissing implied physical contact between our body and that of other people. With respect to touching an inanimate object (objectual touch), touching a person (social touch) concerns not only touching a human body, but also that this body belongs to a living person. This fundamental difference also may affect the way we figure our own movements and perceptions or, in other words, how we mentally represent our own body. To test this hypothesis, we asked 30 neurotypical participants to perform mental rotation of images representing hands, full bodies, and feet (an active cognitive task able to activate body representations without need of moving) in two tactile conditions: holding (one in each hand) either the thumbs of another person (social touch) or two plastic cylinders (objectual touch) of about the same circumference and size. Results showed that only mental rotation of hand images was affected by varying the tactile conditions, in that participants were faster during social than objectual touch. This suggests that the nature of hand-related tactile input (social or objectual touch) influences local (hand) and not global (body) mental representations of the body, and in a very somatotopic manner (hands but not feet). We interpret these findings with reference to the differentiation between sensorimotor (body schema) and visuospatial (body image) dynamics in the mental representation of our body. The present study shows that external social factors can affect the internal mental representations of one's own body.

Effect of neuromorphic transcutaneous electrical nerve stimulation (nTENS) of cortical functional networks on tactile perceptions: an event-related electroencephalogram study.

Background.Transcutaneous electrical nerve stimulation (TENS) is generally applied for tactile feedback in the field of prosthetics. The distinct mechanisms of evoked tactile perception between stimulus patterns in conventional TENS (cTENS) and neuromorphic TENS (nTENS) are relatively unknown. This is the first study to investigate the neurobiological effect of nTENS for cortical functional mechanism in evoked tactile perception.Methods.Twenty-one healthy participants were recruited in this study. Electroencephalogram (EEG) was recorded while the participants underwent a tactile discrimination task. One cTENS pattern (square pattern) and two nTENS patterns (electromyography and single motor unit patterns) were applied to evoke tactile perception in four fingers, including the right and left index and little fingers. EEG was preprocessed and somatosensory-evoked potentials (SEPs) were determined. Then, source-level functional networks based on graph theory were evaluated, including clustering coefficient, path length, global efficiency, and local efficiency in six frequency bands.Main results.Behavioral results suggested that the single motor units (SMUs) pattern of nTENS was the most natural tactile perception. SEPs results revealed that SMU pattern exhibited significant shorter latency in P1 and N1 components than the other patterns, while nTENS patterns have significantly longer latency in P3 component than cTENS pattern. Cortical functional networks showed that the SMU pattern had the lowest short path and highest efficiency in beta and gamma bands.Conclusion.This study highlighted that distinct TENS patterns could affect brain activities. The new characteristics in tactile manifestation of nTENS would provide insights for the application of tactile perception restoration.

The petting factor: Oxytocin and social touch.

In this issue of Neuron, Yu et al. (2022) uncovered a sensory pathway by which social touch can activate oxytocin neurons in the hypothalamus. Their stimulation protocol could deliver pleasant sensory stimuli to juvenile mice, increasing their later-life social interactions.

[Touch Medicine - a complementary therapeutic approach exemplified by the treatment of depression]. / Berührungsmedizin ­ ein komplementärer therapeutischer Ansatz unter besonderer Berücksichtigung der Depressionsbehandlung.

Skin-to-skin-contact presents the earliest sensory experience of men and animals. Deprivation of age-relevant touch experiences during infancy results in compromised psychosocial and biological development. The 2021 Nobel Prize in Physiology or Medicine has been awarded for the discoveries of receptors for temperature and touch. Clinical studies have demonstrated the benefit of professional salutary touch for prevention and treatment of various illnesses. However, in the present practice of medicine the application of salutary touch does not meet adequate interest. Proposing a new medical discipline "Touch Medicine" we link the findings of modern touch research to clinical medicine. The treatment of depression which we conceive primarily as a disease afflicting the body will serve as an example to demonstrate the usefulness of touch therapy. Controlled studies and systematic reviews have convincingly shown antidepressive, anxiolytic and analgesic effects of salutary touch. The effectiveness and efficacy of touch therapy has also been demonstrated in many areas such as neonatology, pediatrics, oncology, and geriatrics. We discuss the underlying mechanisms on various explanatory levels including interoceptive and oxytocinergic mechanisms as well as the role of C tactile afferent nerve fibers.

A self-training program for sensory substitution devices.

Sensory Substitution Devices (SSDs) convey visual information through audition or touch, targeting blind and visually impaired individuals. One bottleneck towards adopting SSDs in everyday life by blind users, is the constant dependency on sighted instructors throughout the learning process. Here, we present a proof-of-concept for the efficacy of an online self-training program developed for learning the basics of the EyeMusic visual-to-auditory SSD tested on sighted blindfolded participants. Additionally, aiming to identify the best training strategy to be later re-adapted for the blind, we compared multisensory vs. unisensory as well as perceptual vs. descriptive feedback approaches. To these aims, sighted participants performed identical SSD-stimuli identification tests before and after ~75 minutes of self-training on the EyeMusic algorithm. Participants were divided into five groups, differing by the feedback delivered during training: auditory-descriptive, audio-visual textual description, audio-visual perceptual simultaneous and interleaved, and a control group which had no training. At baseline, before any EyeMusic training, participants SSD objects' identification was significantly above chance, highlighting the algorithm's intuitiveness. Furthermore, self-training led to a significant improvement in accuracy between pre- and post-training tests in each of the four feedback groups versus control, though no significant difference emerged among those groups. Nonetheless, significant correlations between individual post-training success rates and various learning measures acquired during training, suggest a trend for an advantage of multisensory vs. unisensory feedback strategies, while no trend emerged for perceptual vs. descriptive strategies. The success at baseline strengthens the conclusion that cross-modal correspondences facilitate learning, given SSD algorithms are based on such correspondences. Additionally, and crucially, the results highlight the feasibility of self-training for the first stages of SSD learning, and suggest that for these initial stages, unisensory training, easily implemented also for blind and visually impaired individuals, may suffice. Together, these findings will potentially boost the use of SSDs for rehabilitation.

Post-weaning stroking stimuli induce affiliative behavior toward humans and influence brain activity in female rats.

Gentle touch contributes to affiliative interactions. We investigated the effects of gentle stroking in female rats on the development of affiliative behaviors toward humans and we exploratively examined brain regions in which activity was influenced by stroking. Rats that had received stroking stimuli repeatedly after weaning emitted 50-kHz calls, an index of positive emotion, and showed affiliative behaviors toward the experimenter. Hypothalamic paraventricular oxytocin neurons were activated in the rats after stroking. The septohypothalamic nucleus (SHy) in the post-weaningly stroked rats showed decreased activity in response to stroking stimuli compared with that in the non-stroked control group. There were negative correlations of neural activity in hypothalamic regions including the SHy with the number of 50-kHz calls. These findings revealed that post-weaning stroking induces an affiliative relationship between female rats and humans, possibly via activation of oxytocin neurons and suppression of the activity of hypothalamic neurons.

Whole brain mapping of somatosensory responses in awake marmosets investigated with ultra-high-field fMRI.

The common marmoset (Callithrix jacchus) is a small-bodied New World primate that is becoming an important model to study brain functions. Despite several studies exploring the somatosensory system of marmosets, all results have come from anesthetized animals using invasive techniques and postmortem analyses. Here, we demonstrate the feasibility for getting high-quality and reproducible somatosensory mapping in awake marmosets with functional magnetic resonance imaging (fMRI). We acquired fMRI sequences in four animals, while they received tactile stimulation (via air-puffs), delivered to the face, arm, or leg. We found a topographic body representation with the leg representation in the most medial part, the face representation in the most lateral part, and the arm representation between leg and face representation within areas 3a, 3b, and 1/2. A similar sequence from leg to face from caudal to rostral sites was identified in areas S2 and PV. By generating functional connectivity maps of seeds defined in the primary and second somatosensory regions, we identified two clusters of tactile representation within the posterior and midcingulate cortex. However, unlike humans and macaques, no clear somatotopic maps were observed. At the subcortical level, we found a somatotopic body representation in the thalamus and, for the first time in marmosets, in the putamen. These maps have similar organizations, as those previously found in Old World macaque monkeys and humans, suggesting that these subcortical somatotopic organizations were already established before Old and New World primates diverged. Our results show the first whole brain mapping of somatosensory responses acquired in a noninvasive way in awake marmosets.NEW & NOTEWORTHY We used somatosensory stimulation combined with functional MRI (fMRI) in awake marmosets to reveal the topographic body representation in areas S1, S2, thalamus, and putamen. We showed the existence of a body representation organization within the thalamus and the cingulate cortex by computing functional connectivity maps from seeds defined in S1/S2, using resting-state fMRI data. This noninvasive approach will be essential for chronic studies by guiding invasive recording and manipulation techniques.

Astrocytes Control Sensory Acuity via Tonic Inhibition in the Thalamus.

Sensory discrimination is essential for survival. However, how sensory information is finely controlled in the brain is not well defined. Here, we show that astrocytes control tactile acuity via tonic inhibition in the thalamus. Mechanistically, diamine oxidase (DAO) and the subsequent aldehyde dehydrogenase 1a1 (Aldh1a1) convert putrescine into GABA, which is released via Best1. The GABA from astrocytes inhibits synaptically evoked firing at the lemniscal synapses to fine-tune the dynamic range of the stimulation-response relationship, the precision of spike timing, and tactile discrimination. Our findings reveal a novel role of astrocytes in the control of sensory acuity through tonic GABA release.

Sensory restoration by epidural stimulation of the lateral spinal cord in upper-limb amputees.

Restoring somatosensory feedback to people with limb amputations is crucial to improve prosthetic control. Multiple studies have demonstrated that peripheral nerve stimulation and targeted reinnervation can provide somatotopically relevant sensory feedback. While effective, the surgical procedures required for these techniques remain a major barrier to translatability. Here, we demonstrate in four people with upper-limb amputation that epidural spinal cord stimulation (SCS), a common clinical technique to treat pain, evoked somatosensory percepts that were perceived as emanating from the missing arm and hand. Over up to 29 days, stimulation evoked sensory percepts in consistent locations in the missing hand regardless of time since amputation or level of amputation. Evoked sensations were occasionally described as naturalistic (e.g. touch or pressure), but were often paresthesias. Increasing stimulus amplitude increased the perceived intensity linearly, without increasing area of the sensations. These results demonstrate the potential of SCS as a tool to restore somatosensation after amputations.

Even some of the most advanced prosthetic arms lack an important feature: the ability to relay information about touch or pressure to the wearer. In fact, many people prefer to use simpler prostheses whose cables and harnesses pass on information about tension. However, recent studies suggest that electrical stimulation might give prosthesis users more sensation and better control. After an amputation, the nerves that used to deliver sensory information from the hand still exist above the injury. Stimulating these nerves can help to recreate sensations in the missing limb and improve the control of the prosthesis. Still, this stimulation requires complicated surgical interventions to implant electrodes in or around the nerves. Spinal cord stimulation ­ a technique where a small electrical device is inserted near the spinal cord to stimulate nerves ­ may be an easier alternative. This approach only requires a simple outpatient procedure, and it is routinely used to treat chronic pain conditions. Now, Chandrasekaran, Nanivadekar et al. show that spinal cord stimulation can produce the feeling of sensations in a person's missing hand or arm. In the experiments, four people who had an arm amputation underwent spinal cord stimulation over 29 days. During the stimulation, the participants reported feeling electrical buzzing, vibration, or pressure in their missing limb. Changing the strength of the electric signals delivered to the spinal cord altered the intensity of these sensations. The experiments are a step toward developing better prosthetics that restore some sensation. Further studies are now needed to determine whether spinal cord stimulation would allow people to perform sensory tasks with a prosthetic, for example handling an object that they cannot see.

Enhanced Pitch Discrimination for Cochlear Implant Users with a New Haptic Neuroprosthetic.

The cochlear implant (CI) is the most widely used neuroprosthesis, recovering hearing for more than half a million severely-to-profoundly hearing-impaired people. However, CIs still have significant limitations, with users having severely impaired pitch perception. Pitch is critical to speech understanding (particularly in noise), to separating different sounds in complex acoustic environments, and to music enjoyment. In recent decades, researchers have attempted to overcome shortcomings in CIs by improving implant technology and surgical techniques, but with limited success. In the current study, we take a new approach of providing missing pitch information through haptic stimulation on the forearm, using our new mosaicOne_B device. The mosaicOne_B extracts pitch information in real-time and presents it via 12 motors that are arranged in ascending pitch along the forearm, with each motor representing a different pitch. In normal-hearing subjects listening to CI simulated audio, we showed that participants were able to discriminate pitch differences at a similar performance level to that achieved by normal-hearing listeners. Furthermore, the device was shown to be highly robust to background noise. This enhanced pitch discrimination has the potential to significantly improve music perception, speech recognition, and speech prosody perception in CI users.

Imagery-induced negative affect, social touch and frontal EEG power band activity.

Social touch seems to modulate emotions, but its brain correlates are poorly understood. Here, we investigated if frontal power band activity in the electroencephalogram (EEG) during aversive mental imagery is modulated by social touch from one's romantic partner and a stranger. We observed the highest theta and beta power when imaging alone, next so when being touched by a stranger, with lowest theta and beta activity during holding hands with the loved one. Delta power was higher when being alone than with a stranger or a partner, with no difference between the two. Gamma power was highest during the stranger condition and lower both when being alone and with the partner, while alpha power did not change as a function of social touch. Theta power displayed a positive correlation with electrodermal activity supporting its relation to emotional arousal. Attachment style modulated the effect of touch on the EEG as only secure but not insecure partner bonding was associated with theta power reductions. Because theta power was sensitive to the experimental perturbations, mapped onto peripheral physiological arousal and reflected partner attachment style we suggest that frontal theta power might serve as an EEG derived bio-marker for social touch in emotionally significant dyads.

Altered resting activity patterns and connectivity in individuals with complex regional pain syndrome.

Complex regional pain syndrome (CRPS) is a chronic neuropathic pain disorder that typically occurs in the limbs, usually the upper limb. CRPS usually develops from a peripheral event but its maintenance relies on changes within the central nervous system. While functional abnormalities in the thalamus and primary somatosensory cortex (S1) of the brain are some of the most consistently reported brain findings in CRPS, the mechanisms are yet to be explored in full, not least of all how these two regions interact and how they might relate to clinical deficits, such as the commonly reported poor tactile acuity in this condition. This study recruited 15 upper-limb CRPS subjects and 30 healthy controls and used functional magnetic resonance imaging (fMRI) to investigate infra-slow oscillations (ISOs) in critical pain regions of the brain in CRPS. As hypothesised, we found CRPS was associated with increases in resting signal intensity ISOs (0.03-0.06 Hz) in the thalamus contralateral to the painful limb in CRPS subjects. Interestingly, there was no such difference between groups in S1, however CRPS subjects displayed stronger thalamo-S1 functional connectivity than controls, and this was related to pain. As predicted, CRPS subjects displayed poor tactile acuity on the painful limb which, interestingly, was also related to thalamo-S1 functional connectivity strength. Our findings provide novel evidence of altered patterns of resting activity and connectivity in CRPS which may underlie altered thalamocortical loop dynamics and the constant perception of pain.

The rubber hand illusion in hypnosis provides new insights into the sense of body ownership.

Body ownership can be experimentally investigated with the rubber hand illusion (RHI), in which watching a rubber hand stroked synchronously with one's own hidden hand induces a feeling of ownership over the rubber hand. The aim of this study was to investigate response to the RHI in high (N = 21) and low (N = 19) hypnotizable individuals in normal waking state and in hypnosis. Response to the RHI was measured via a question on the illusory feeling of ownership and with proprioceptive drift. The Highs expressed an overall feeling of more ownership over the rubber hand in both the normal waking state and hypnosis, although both groups gave higher ownership scores after synchronous than after asynchronous stroking and the difference between conditions was similar across groups. Conversely, the proprioceptive drift appeared to be differentially modulated by hypnosis and hypnotic suggestibility: it was increased in the Highs and decreased in the Lows after hypnosis induction. These findings hint at an interplay between hypnotic suggestibility and hypnosis in modulating response to the RHI. The selective breakdown of proprioceptive drift among the Lows suggests resistance to recalibrate one's own limb in hypnosis.

Decoding across sensory modalities reveals common supramodal signatures of conscious perception.

An increasing number of studies highlight common brain regions and processes in mediating conscious sensory experience. While most studies have been performed in the visual modality, it is implicitly assumed that similar processes are involved in other sensory modalities. However, the existence of supramodal neural processes related to conscious perception has not been convincingly shown so far. Here, we aim to directly address this issue by investigating whether neural correlates of conscious perception in one modality can predict conscious perception in a different modality. In two separate experiments, we presented participants with successive blocks of near-threshold tasks involving subjective reports of tactile, visual, or auditory stimuli during the same magnetoencephalography (MEG) acquisition. Using decoding analysis in the poststimulus period between sensory modalities, our first experiment uncovered supramodal spatiotemporal neural activity patterns predicting conscious perception of the feeble stimulation. Strikingly, these supramodal patterns included activity in primary sensory regions not directly relevant to the task (e.g., neural activity in visual cortex predicting conscious perception of auditory near-threshold stimulation). We carefully replicate our results in a control experiment that furthermore show that the relevant patterns are independent of the type of report (i.e., whether conscious perception was reported by pressing or withholding a button press). Using standard paradigms for probing neural correlates of conscious perception, our findings reveal a common signature of conscious access across sensory modalities and illustrate the temporally late and widespread broadcasting of neural representations, even into task-unrelated primary sensory processing regions.